What’s the frequency? Advertisers deal with conflicting data

It might be hard to believe based on what you see, but some marketers are trying not to inundate people with the same ads over and over.

But this so-called "frequency capping"a strategy growing in popularityis easier said than done. How much is too much? It depends whom you ask. Research suggests the optimal number varies by medium, category, objective and type of ad. Then, even if you have a number in mind, tools to enforce that cap are inconsistent.

Individual brands, however, are giving it a shot. Procter & Gamble, for one, says it tries not to show its digital ads to people more than three times a month. But realistically, people may see some of its TV ads more often than that, especially on cable, where there are a lot of repeated shows. And some researchers believe three isn't enough anyway.